Some projects on ESP8266 boards

ESP8266 sensing CO2 + Temp + RH + Pressure

By Atomstar on Friday 20 December 2019 16:20 - Comments (9)
Categories: ESP8266, Smarthome, Views: 3.324

I've progressed somewhat in home-integrated sensors, and I've established a baseline for a connected home-environment sensor, which I document here.

ESP8266 Lolin d1 mini pro kit back

Read more »

Flash problems to ESP8266 boards

By Atomstar on Thursday 21 November 2019 21:32 - Comments (1)
Category: ESP8266, Views: 1.559

Note to self: sometimes I cannot write to ESP8266 boards. The solution appeared to be to disconnect serial devices first (e.g. MH-Z19B), then flash

Symptoms

  • Typically freshly bought boards (Wemos D1 mini Pro) running micropython
  • esptool.py reports: A fatal error occurred: Failed to connect to Espressif device: Timed out waiting for packet header
  • Arduino reports: error: espcomm_open failed error: espcomm_upload_mem failed
  • Cannot interact or write to Micropython REPL prompt, commands are not fed back (i.e. I only have RX no TX capability)

Diagnosing ESP8266 boards

To see what the board is doing, connect to USB, then run screen on the tty:
screen /dev/tty.usbserial-1420 {74880,115200}

Or use Arduino 'Serial logger'. Use baud 74880 for boot loader, 115200 for programs running on the board (in my case). This gave me:

21:32:09.624 -> OSError: [Errno 2] ENOENT
21:32:09.624 -> 
21:32:09.624 -> MicroPython v1.9.4-8-ga9a3caad0 on 2018-05-11; ESP module with ESP8266
21:32:09.624 -> Type "help()" for more information.
21:32:09.624 -> >>> 


Once I found the board was running Micropython (i.e. ruling out HW problem), I found that I could connect but not write to the Micropython prompt.

Solution

In my case the problem appeared to be that a sensor using the serial port blocked my input to the serial port for uploading. Disconnecting the sensor worked. HTH.

Measuring CO2 using MH-Z19B and D1 mini pro

By Atomstar on Thursday 20 December 2018 20:59 - Comments (0)
Categories: ESP8266, Smarthome, Views: 2.743

In this article I describe how to measure CO2 levels using an MH-Z19B CO2 sensor connected to D1 mini pro and push these somewhere over wifi.

Read more »

Getting started with LOLIN D1 mini/DHT22 on Mac

By Atomstar on Thursday 20 December 2018 16:06 - Comments (5)
Categories: ESP8266, Smarthome, Views: 2.089

To augment my smarthome hub and feed it with more data, I'm experimenting with LOLIN ESP8266 boards from WeMos. Specifically, I have the LOLIN D1 mini Pro v2.0.0. In this post I document how I overcame some hurdles in getting this to work. See also this WeMos tutorial.

Read more »